Desmond gerald fitz-gekald



quently attached to the molded'A plates or masses, The molded plates or masses Vare then exposed to an atmosphere containing carbonic acid (preferably to a currenty of air containing the fullnormal o'r an increased percentage ofcarbonicacid) for' a sufficient period of this exposure is partially to dry the plates or other masses and by the conversion of the caustic into carbonated alkali, to precipitate the oxide of lead previously held in solution. When such precipitation has occurred to a suflcientl extent, the material sets v and will no longer disintegrate when immersed in an aqueous'iuid. The set plates or masses are then dipped for a few seconds in a solution -of sulphate of magnesia which may be halfsaturated or more dilute. Thisdipping should be at least twice repeated at vintervals of a day or more and be dried by exposure to air after eachimmersion. The sulphate solution' used for the last immersion should be more dilute than the preceding solutions and should be slightly acidulated with sulphuric acid and the plates may advantageously be left for 4so'me hours in this acidulated solution 'with a View to dissolve out precipitated nlagnesium hydrate. The plates or masses should afterward be stood in a rack to drain and dry, and become seasoned. The plates or masses may be reduced to spongy lead orperoxidized by .the ordinary means.

B.-A modification of the above process adapted for the production ot plates of greater porosity, is to subject litharge or massicot or minium, or a mixture of them, preferably-in a slightly damp condition, toA pressure in a mold between sheets of a material, such as linen or felt, containing enough moisture to cause the surface particles ot the lead oxide or oxides to cohere suiciently to allow of the subsequent treat'ment of the molded mass (either within the mold or otherwise suplported,as by a plate of glass) with an alkaline solution such as is'above specified," the treatment in this case being conveniently effected by gently pouringa suicient quantity of the caustic solution over the" molded mass. The subsequent steps in this process'e-i. e. exposure to carbonio acid and treatment with sulphate solution-are similarto those above described.

0.-In a third process,a mixture or any l one or more of the lower oxides of lead with peroxide of lead is used which may contain twenty-live per cent. or more of the latter in'- gredient. The mixture may either be made scemo into a paste with the .caustic solution `or be 'molded dry and moistened with the caustic solution as in the methods above mentioned.

In this case the treatment with the'alkali'ne solution causes the plate or mass to quickly set into a hard porous condition, even without the intervention 'ofcarbonicacid that exposure to that gas for alonger period than a few hours and subsequent treatment with sulphate of maguesia are not in this case es-r sential.

It is to be observed that the proportion of peroxide contained in the mixture to be treated may be such that t process becomes practically one fort-he utili ation of peroxide of lead, whether'produced chemically or electrolytically.4 I prefer, however, that the proportion of. the lower oxide present should not be less than, say, ten per cent. or thereabout, in order to produce with certainty. the f setting elect desired.

The plate or mass being initially conductive is, for this reason as well as from the fact that it may be regarded as partly. formed, rapidly convertible wholly into peroxide by -the passage ofthe current.

I would observe that I have given the above processes as examples of the mode in which I usually carry my invention into elect, but I do not limit myself thereto.

I claim- 1 f 2. The herein described process et" man-u factoring batteryelectrodes which consists in;

1. The herein described 'process of manu-` treating litharge with a solution ofcaustic f potash, converting the caustic alklali into carbonated alkali by exposure to carbonio acid, and` treatingthe resulting mass with sulphate of magnesia, as specified.v

3. The herein described process of manufacture of battery plates which. consists in treatingfa mixture of litharge'andminium y with a mixture of caustic potash and caustic soda .in solution, con vertingthe caustic alkali into carbonated alkali by exposure to carbonio acid, and treating" the resulting mass with sulphate of magnesia, as specified.

1 Signed by thesaid Dus-Mom) GERALD Frrz- GERALD.

, DESMOND 'GERALD FITZ-GERLD.

In presence of- G. F. WARREN,

Notary Public, London; THOMAS LAKE,

17 Hracechurch Street, London. 

